Hi maverickx--
It really isn't possible to ID the shades of this stamp from computer images. If 100 of us look at the image, we'll get many, many different results because not everyone is calibrated the same.
The Rose Brown shade was produced in 1865, and is fairly common, and once you see it, it's fairly easy to ID. Hope that this image helps-- this is the Rose Brown from 1865:

Again, I can't predict what it would look like on your monitor. The best way to ID shades of this issue is by collecting on cover, with month and year dates. Several past issues in "The Chronicle" from the US Philatelic Classics Society lists and describes the 54 various shades, most of which aren't listed in Scott, and most have never been published in color for comparison. I was fortunate to buy many covers from Mike McClung, who is the person who ID'd the many shades by month and year date, and authored the Chronicle articles.
If you look back at my postings over the past 5 years, you'll see where I have posted many of the shades in high res images...hope this all helps you. Ray
Hope this helps, Ray